1. Field of the Invention
The present invention, relates to a technique of measuring a heart rate of a user.
2. Background Art
There is a heartbeat measuring device which is mounted on the exercising user's body and measures a heart rate of the user (for example, JP-A-3-159634). The heartbeat measuring device detects an electrocardiogram signal occurring due to the heartbeat of the user and calculates a heart rate according to the pulse interval of the electrocardiogram signal. Here, there are cases where an incorrect electrocardiogram signal is detected depending on a degree of adhesion between the heartbeat we as urine device and the skin of the user or the like. For example, in a case where a signal which is not an electrocardiogram signal is detected as the electrocardiogram signal, a pulse interval decreases, and thus an abnormally high heart rate is calculated. Alternatively, in a case where detection of an electrocardiogram signal is omitted, a pulse interval increases, and thus an abnormally low heart rate is calculated. It can be said that the heart rate calculated in this way is an abnormal value and is an invalid heart rate. Therefore, a threshold value of a heart rate for determining whether or not a heart rate is a normal value may be stored in a heartbeat measuring device in advance, and whether or not a valid heart rate has been measured may be determined by comparing the measured heart rate and a predefined threshold value.
However, since heart rates are different depending on the age, the stature, the weight, the sex, the exercise frequency, and the like of a user, there may be cases where an invalid heart rate is determined as being a normal value if a heart rate of another user is compared with the same threshold value. Therefore, even in this case, whether or not a measured heart rate is a normal value is preferably determined.